I just recently became oneworld sapphire (through BA Silver), after being Star Gold for a long time (thru SQ PPS).

Have been travelling oneworld quite a fair bit lately now. A few things have pleasantly surprised me about ow -- the chief thing being ability to use any oneworld airport lounge as a ow sapphire even when flying economy, as long as I on flying a ow carrier. Can even use AA ACs for domestic US flights as a BA ow sapphire! Amazing perk!

Being SQ PPS allows me to use SQ lounges only when flying economy, and that too only when flying SQ. Other than that, Star's lounge access seems similar to oneworlds for elite members

I also like many of the oneworld airlines -- have some good airlines there in BA, CX, JL, QF, and arguably the most premium US airlines, AA. A more "exclusive" club than Star, though Star has its stars -- SQ being exhibit #1!

What do I not like about oneworld -- well, the most obvious thing is the lack of mileage earn / burn when across the Atlantic on AA when flying BA and vice-versa. A huge gap, which I am hoping they fix fast!

What are your thoughts on advantages and disadvantages of oneworld relative to the other alliances? Going forward, if you had to stick to one (may be hard for me to retain status on both ow and star), which one would you pick?